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Dive into the research topics where Michael P. Porter is active.

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Featured researches published by Michael P. Porter.


Cancer | 2008

The association between extent of lymphadenectomy and survival among patients with lymph node metastases undergoing radical cystectomy.

Jonathan L. Wright; Daniel W. Lin; Michael P. Porter

Long‐term survival in patients with lymph node‐positive bladder cancer who undergo cystectomy suggests a therapeutic role for lymphadenectomy. The objective of this study was to describe the association between extent of lymphadenectomy and survival in lymph node‐positive patients who underwent radical cystectomy.


Clinical Cancer Research | 2009

Disseminated Tumor Cells in Prostate Cancer Patients after Radical Prostatectomy and without Evidence of Disease Predicts Biochemical Recurrence

Todd M. Morgan; Paul H. Lange; Michael P. Porter; Daniel W. Lin; William J. Ellis; Ian S. Gallaher; Robert L. Vessella

Purpose: Men with apparently localized prostate cancer often relapse years after radical prostatectomy. We sought to determine if epithelial-like cells identified from bone marrow in patients after radical prostatectomy, commonly called disseminated tumor cells (DTC), were associated with biochemical recurrence. Experimental Design: We obtained bone marrow aspirates from 569 men prior to radical prostatectomy and from 34 healthy men with prostate-specific antigens <2.5 ng/mL to establish a comparison group. Additionally, an analytic cohort consisting of 98 patients with no evidence of disease (NED) after radical prostatectomy was established to evaluate the relationship between DTC and biochemical recurrence. Epithelial cells in the bone marrow were detected by magnetic bead enrichment with antibodies to CD45 and CD61 (negative selection) followed by antibodies to human epithelial antigen (positive selection) and confirmation with FITC-labeled anti-BerEP4 antibody. Results: DTC were present in 72% (408 of 569) of patients prior to radical prostatectomy. There was no correlation with pathologic stage, Gleason grade, or preoperative prostate-specific antigens. Three of 34 controls (8.8%) had DTC present. In patients with NED after radical prostatectomy, DTC were present in 56 of 98 (57%). DTC were detected in 12 of 14 (86%) NED patients after radical prostatectomy who subsequently suffered biochemical recurrence. The presence of DTC in NED patients was an independent predictor of recurrence (hazard ratio 6.9; 95% confidence interval, 1.03-45.9). Conclusions: Approximately 70% of men undergoing radical prostatectomy had DTC detected in their bone marrow prior to surgery, suggesting that these cells escape early in the disease. Although preoperative DTC status does not correlate with pathologic risk factors, persistence of DTC after radical prostatectomy in NED patients was an independent predictor of recurrence.


The Journal of Urology | 2008

Radiation therapy for prostate cancer increases subsequent risk of bladder and rectal cancer: a population based cohort study.

Alan M. Nieder; Michael P. Porter; Mark S. Soloway

PURPOSE Pre-prostate specific antigen era series demonstrated an increased risk of bladder cancer and rectal cancer in men who received radiotherapy for prostate cancer. We estimated the risk of secondary bladder cancer and rectal cancer after prostate radiotherapy using a contemporary population based cohort. MATERIALS AND METHODS We identified 243,082 men in the Surveillance, Epidemiology and End Results database who underwent radical prostatectomy or radiotherapy for prostate cancer between 1988 and 2003. We estimated the incidence rate, standardized incidence ratio and age adjusted incidence rate ratio of subsequent bladder cancer and rectal cancer associated with radical prostatectomy, external beam radiotherapy, brachytherapy, and a combination of external beam radiotherapy and brachytherapy. RESULTS The relative risk of bladder cancer developing after external beam radiotherapy, brachytherapy and external beam radiotherapy-brachytherapy compared to radical prostatectomy was 1.88, 1.52 and 1.85, respectively. Compared to the general United States population the standardized incidence ratio for bladder cancer developing after radical prostatectomy, external beam radiotherapy, brachytherapy and external beam radiotherapy-brachytherapy was 0.99, 1.42, 1.10 and 1.39, respectively. The relative risk of rectal cancer developing after external beam radiotherapy, brachytherapy and external beam radiotherapy-brachytherapy compared to radical prostatectomy was 1.26, 1.08 and 1.21, respectively. The standardized incidence ratio for rectal cancer developing after radical prostatectomy, external beam radiotherapy, brachytherapy and external beam radiotherapy-brachytherapy was 0.91, 0.99, 0.68 and 0.86, respectively. CONCLUSIONS Men who receive radiotherapy for localized prostate cancer have an increased risk of bladder cancer compared to patients undergoing radical prostatectomy and compared to the general population. The risk of rectal cancer is increased in patients who receive external beam radiotherapy compared to radical prostatectomy. Patients should be counseled appropriately regarding these risks.


Cancer | 2009

Treatment and survival outcomes in young men diagnosed with prostate cancer: a population based cohort study

Daniel W. Lin; Michael P. Porter; Bruce Montgomery

Outcomes of treatment for young men compared with older men with prostate cancer are poorly defined outside of limited institutional series. In this study, the authors examined the association between age at diagnosis and grade, stage, treatment, and survival outcomes in men who were diagnosed during the era of prostate‐specific antigen testing.


Cancer | 2006

Differences in survival among patients with urachal and nonurachal adenocarcinomas of the bladder

Jonathan L. Wright; Michael P. Porter; Christopher I. Li; Paul H. Lange; Daniel W. Lin

Primary adenocarcinomas of the bladder and urachus are rare malignancies, and knowledge of the patient demographics, pathologic characteristics, and survival associated with these tumors is poor. The current study compares disease‐specific characteristics and survival associated with urachal and nonurachal primary bladder adenocarcinomas.


Urologic Oncology-seminars and Original Investigations | 2011

Patterns of use of systemic chemotherapy for Medicare beneficiaries with urothelial bladder cancer

Michael P. Porter; Matthew Kerrigan; Bm Donato; Scott D. Ramsey

OBJECTIVES Examine the association between clinical, demographic, and socioeconomic factors and the receipt of systemic chemotherapy for bladder cancer. Examine factors influencing the use of combination chemotherapy plus cystectomy and use of specific chemotherapy drugs over time for bladder cancer. MATERIALS AND METHODS Data from the SEER-Medicare database were analyzed for patients diagnosed with urothelial carcinoma of the bladder between 1992 and 2002. Cox proportional hazards regression analyses were used to assess differences in use of systemic chemotherapy based on demographic and clinical factors, site of care, and year of diagnosis. We assessed the proportion of patients who received chemotherapy in the adjuvant and neoadjuvant settings as well as use of chemotherapy in the monotherapy setting. We estimated the proportion of claims made for several commonly used chemotherapy agents in the outpatient setting by year. RESULTS During follow-up, 13%, 28%, 37%, and 57% of patients with stages 1 through 4, respectively, received systemic chemotherapy for bladder cancer. Chemotherapy use in the neoadjuvant or adjuvant settings within 6 months of diagnosis was not commonly found. Neoadjuvant chemotherapy was delivered to 1.4% of stage 2 patients and 11% of stage 4 patients. In 2003, the most frequent claims for intravenous chemotherapy were for gemcitabine, carboplatin, and placlitaxel. CONCLUSIONS Chemotherapy was not generally used as recommended for persons with invasive bladder cancer in this patient population. Studies to clarify potential underutilization and variation in patterns of administration are warranted.


Pediatrics | 2005

Hypospadias in Washington State: Maternal Risk Factors and Prevalence Trends

Michael P. Porter; M. Khurram Faizan; Richard W. Grady; Beth A. Mueller

Objective. Maternal risk factors for hypospadias are poorly defined, and there is debate about temporal trends in hypospadias prevalence. We examined select maternal characteristics as possible risk factors for hypospadias among male offspring and evaluated yearly prevalence rates in Washington State. Methods. We performed a population-based, case-control study using linked birth-hospital discharge data from Washington State for 1987–1997 and prevalence data for 1987–2002. All cases of hypospadias were identified on the basis of International Classification of Diseases, Ninth Revision, codes from the birth hospitalization (N = 2155). Five control subjects were randomly selected for each case subject from the remaining singleton births, frequency matched according to year of birth (N = 10775). Maternal and infant characteristics were ascertained from the birth certificate. Logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Yearly prevalence was determined by dividing the total number of hypospadias cases by the number of male singleton live births for each year. Results. The risk of delivering an affected male infant increased with advancing maternal age; relative to women <20 years of age, those >40 years of age were at greatest risk (OR: 1.70; 95% CI: 1.17–2.48). Infants of nonwhite women were generally at decreased risk. Infants born to women with preexisting diabetes mellitus were at greater risk than those born to women without diabetes (OR: 2.18; 95% CI: 1.03–4.60); however, this was not observed for infants born to women with gestational diabetes. The birth prevalence of hypospadias in 2002 was 5.0 cases per 1000 male births, not significantly different from that in 1987. Conclusion. Older maternal age, white race, and preexisting diabetes were associated with increased risk of hypospadias among male offspring. The prevalence of hypospadias in Washington State did not increase significantly between 1987 and 2002.


Obstetrics & Gynecology | 2007

Admission for nephrolithiasis in pregnancy and risk of adverse birth outcomes.

Mia A. Swartz; Mona T. Lydon-Rochelle; David Simon; Jonathan L. Wright; Michael P. Porter

OBJECTIVE: Nephrolithiasis occurring during pregnancy may be associated with an elevated risk of preterm delivery and other adverse birth outcomes. The goal of this study was to describe the association between these outcomes and admission for nephrolithiasis during pregnancy. METHODS: We performed a retrospective cohort study using birth certificate records linked to Washington State hospital discharge data from 1987–2003 to compare pregnant women admitted for nephrolithiasis and randomly selected pregnant women without nephrolithiasis. The main outcomes of interest were preterm delivery, premature rupture of membranes at term or before 37 weeks of gestation, low birth weight, and infant death. RESULTS: A total of 2,239 women were admitted for nephrolithiasis, yielding a cumulative incidence of 1.7 admissions per 1,000 deliveries. Women admitted for nephrolithiasis during pregnancy had nearly double the risk of preterm delivery compared with women without stones (adjusted odds ratio 1.8, 95% confidence interval 1.5–2.1). However, they were not at higher risk for the other outcomes investigated. A total of 471 (25.9%) women had one or more procedures for kidney stones during prenatal hospitalization. Undergoing a procedure and the trimester of admission did not affect the risk of preterm delivery. CONCLUSION: Although the incidence of nephrolithiasis requiring hospital admission during pregnancy is relatively low, these women have an increased risk of preterm delivery. This has potential implications for counseling of pregnant women with kidney stones requiring hospital admission. Additionally, it may prompt definitive treatment of small, asymptomatic stones in women during reproductive years. LEVEL OF EVIDENCE: II


Nature Clinical Practice Urology | 2007

Quality-of-life assessment in patients with bladder cancer

Jonathan L. Wright; Michael P. Porter

Health-related quality of life (HRQOL) in patients with bladder cancer is important, because radical cystectomy and urinary diversion significantly affect urinary and sexual function, and lead to associated sex-specific morbidity. This article reviews the current methods for defining HRQOL, describes the specific challenges in measuring HRQOL in patients with bladder cancer, and critically analyzes the existing literature on bladder cancer HRQOL. Previous studies have been limited by study design, generalizability, and by the different instruments used, namely nonvalidated questionnaires that are not specific for bladder cancer. To date, only two prospective studies with baseline HRQOL data have been published and few conclusions can be drawn from these cross-sectional, retrospective studies. On the basis of the published literature, there is no convincing evidence that superior HRQOL is achieved with a particular type of urinary diversion after cystectomy for bladder cancer. Patients should be counseled on all reconstructive alternatives and a diversion chosen on the basis of patient preference, patient anatomy and tumor status, rather than on a potential difference in HRQOL. Prospective studies with appropriate adjustment for confounding factors, which use validated and disease-specific questionnaires, are needed for HRQOL research on bladder cancer.


Cancer | 2009

Key concerns about the current state of bladder cancer: A position paper from the Bladder Cancer Think Tank, the Bladder Cancer Advocacy Network, and the Society of Urologic Oncology

Yair Lotan; Ashish M. Kamat; Michael P. Porter; Victoria L. Robinson; Neal Shore; Michael A.S. Jewett; Paul F. Schelhammer; Ralph W. deVere White; Diane Zipursky Quale; Cheryl T. Lee

Bladder cancer is the fifth most common cancer in the United States and, on a per capita basis, is the most expensive cancer from diagnosis to death. Unfortunately, National Cancer Institute funding for bladder cancer is quite low when compared with other common malignancies. Limited funding has stifled research opportunities for new and established investigators, ultimately encouraging them to redirect research efforts to other organ sites. Waning interest of scientists has further fueled the cycle of modest funding for bladder cancer. One important consequence of this has been a lack of scientific advancement in the field. Patient advocates have decidedly advanced research efforts in many cancer sites. Breast, prostate, pancreatic, and ovarian cancer advocates have organized highly successful campaigns to lobby the federal government and the medical community to devote increased attention and funding to understudied malignancies and to conduct relevant studies to better understand the therapy, diagnosis, and prevention of these diseases. Bladder cancer survivors have lacked a coordinated advocacy voice until recently. A concerted effort to align bladder cancer advocates, clinicians, and urologic organizations is essential to define the greatest needs in bladder cancer and to develop related solutions. This position paper represents a collaborative discussion to define the most concerning trends and greatest needs in the field of bladder cancer as outlined by the Bladder Cancer Think Tank, the Bladder Cancer Advocacy Network, and the Society of Urologic Oncology. Cancer 2009.

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John L. Gore

University of Washington

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Daniel W. Lin

University of Washington

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Sarah K. Holt

University of Washington

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Andrew James

University of Washington

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Paul H. Lange

University of Washington

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Ashish M. Kamat

University of Texas MD Anderson Cancer Center

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